Project M21 - Building the Ultimate Airsoft DMR - Part #2: The Gearbox
Okay, I will start by saying that this part made me question the whole project. Was this really what I wanted to do? Is it all worth it? There was some extreme self doubt during this stage.
It all started one evening after work. I walked home and got back with plenty of time to use for what I knew would be the most challenging part, having the luxury of finishing at 2pm; don't worry, such a privilege comes with a stupidly early start. I got back and decided to have a go at installing all these shiny new parts I had received, as I have a strong feeling towards airsoft sniping, as a long time fan of it. I believe that everyone who wants to get into airsoft sniping should have to upgrade their rifles themselves, so they know exactly what has gone in and how it will work, as well as acting as a natural dissuasion from starting with a sniper rifle, which is one of the biggest mistakes in airsoft. I loaded up a video on how to disassemble a TM m14 and got to work.
The gearbox bit was actually fine. Removing the items inside was easy, and replacing them with the new ones that I covered in teflon grease was a walk in the park, if a bit messy. It definitely helped that the Guarder tune up kit I bought was However, actually getting to that stage and putting everything back in the right place was an absolute nightmare. For those of you who don't know, all the trigger contacts, fire selector and all that stuff that's inside a version 2 gearbox is mounted on the outside of the version 7. There are so many tiny screws and tiny hooky springs to keep track of that I wouldn't advise ever taking it apart without some sort of tray to put all these items in. Furthermore, it helps to either place them down in a way where you know where they will go when you put it back together, or draw a diagram of the outside and place the pieces down in corresponding positions once removed. Regardless, I soldiered on, hating myself as the hours passed by.
Seven hours later and it was all done and back together. I cycled some BBs through it, using some of the new stubby magazines that I had for it to find it wasn't feeding properly. Fortunately, I discovered this was the magazines and not the gun itself as I cycled through a bunch of shots from a normal TM low-cap and it worked just fine. I swear I was on the brink of giving up when I found those feeding issues...
The next skirmish day I took it down to my local site and we chronoed it, as I wanted to make sure it was firing consistently and there wasn't anything causing wild fluctuations in the power. The results came in at 1.4J on .25s, but as I took it to the range I found the stock hop rubber wasn't able to lift .32s, keeping its effective range down near that of my TM416, only with an MED which my 416 (which fires at about 0.7J) doesn't have.
Also, as luck would have it, one part did snap while I was putting it back together. However, this was a stroke of good luck, rather than bad, as the part that snapped was part of the fire selector that moved back and forth as I change between full auto and semi-auto, effectively locking it to semi-automatic. With the new power, this is exactly what I wanted to do, as the power was now beyond the limit for full-auto RIFs.
I've done it now though. I did the most difficult part of the upgrade. The next parts to document are easy; the barrel and hop rubber, which I've done before with ease, as well as the externals, which I don't see as having the same difficulty as what I have endured in upgrading the power in this. If it breaks down, or when the gearbox needs some maintenance, I'm going to get a tech to do it in future. I never want to go through that again, but I am glad that I did. Just don't expect me to upgrade another m14 platform. Ever. (even though it is my favourite platform)
Any airsoft sniper should upgrade their rifles themselves, so they know how it works in and out.